In the trucking industry, remote batteries located on a trailer have traditionally been charged by coupling the electrical system of the truck to the remote batteries (e.g., liftgate electrical system) by using large cables and connections. An example of this is a dual-pole connection between the tractor and the trailer. Because of the long distance, the voltage drops in the cables and in the connection causes a reduction in the power that can be delivered to the liftgate batteries. This results in batteries that do not get optimally charged and therefore may not function as well or last as long as would be expected or needed. To improve the charging of remotely located batteries, the prior art has incorporated battery chargers (e.g., DC-DC converters). These DC-DC converters have been utilized in the trucking industry for several years to charge auxiliary batteries (e.g., liftgate batteries) that are located a distance from the vehicle's main electrical system. One method of charging the liftgate batteries is disclosed in U.S. Pat. No. 8,004,242 (“System and method for managing distribution of vehicle power in a multiple battery system”), which is incorporated herein by reference in its entirety. The benefits of properly charging batteries to their function and life is well-known and documented. With or without a DC-DC converter, the liftgate charging system could cease to function properly due to the effects of aging, wear, or damage. It requires very little electrical energy to lower a liftgate, but it requires a significant amount of energy to raise a liftgate. Because of this fact, when a liftgate electrical system fails, the result is often a liftgate that is stuck in the lowered position, which can prevent the vehicle from being moved. When this happens, it can be very expensive, in both direct and indirect costs, to remedy the problem.
Therefore, there remains a need for a system that can monitor battery charging systems. There is a further need to not only monitor, but to extend the life of the systems being monitored. Even more, in a system with multiple power sources, there is a need to not only charge auxiliary batteries, but to also monitor and display the status of the various electrical components involved, and, ideally, select the best source for charging the auxiliary batteries. The present invention solves these and other problems.